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Reciprocal changes in the postnatal expression of the sarcolemmal Na+-Ca2+-exchanger and SERCA2 in rat heart

Item Type:Article
Title:Reciprocal changes in the postnatal expression of the sarcolemmal Na+-Ca2+-exchanger and SERCA2 in rat heart
Creators Name:Vetter, R. and Studer, R. and Reinecke, H. and Kolar, F. and Ostadalova, I. and Drexler, H.
Abstract:The aim of this study was to examine the relationship between sarcolemmal Na(+)-Ca2+ exchangers and sarcoplasmic reticulum (SR) Ca(2+) -ATPase (SERCA2) expression and the developmental differences in cardiac Ca2+ handling. Postnatal steady-state mRNA and protein levels were analysed in rat ventricular myocardium by Northern and immunoblot analysis, respectively. This was compared to Na+ gradient-induced and SR oxalate-supported Ca2 transport in isolated membranes. Na(+)-Ca2+ exchanger mRNA declined by 75% between day 1 and 30, whereas SR Ca2+ ATPase mRNA levels increased by 97% during this period. The Na(+)-Ca2+ exchanger mRNA/Ca(2+)-ATPase mRNA ratio was found to be inversely related to post-natal age. The changes in mRNA levels were associated with corresponding developmental differences in the Ca2+ transport activities of the respective membrane proteins. In crude membranes, the Na(+)-dependent Ca2+ transport activity (at 75 microM Ca2+) declined gradually (P < 0.01; mean +/- S.E.) from 17.7 +/- 2.4 nmoles Ca2+/g wet tissue/2s at day 1-3 (n = 5) to a value of 4.2 +/- 1.1 at day 40 (n =4). Conversely, SR Ca2+ uptake increased (P < 0.01) 2.6-fold during this period. The inversely related changes in the post-natal expression and function of the Na(+)-Ca2+ exchanger and SR Ca(2+)-ATPase suggest a coordinated control at the pretranslational level of the cellular Ca2+ transport processes mediated by the two membrane proteins.
Keywords:Growth, Sarcoplasmic Reticulum, Sarcolemma, Calcium ATPase, Sodium-Calcium Exchange, Development, mRNA, Postextrasystolic Potentiation, Gene Expression, Animals, Rats
Source:Journal of Molecular and Cellular Cardiology
Page Range:1689-1701
Date:1 August 1995
Official Publication:https://doi.org/10.1016/S0022-2828(95)90788-2
PubMed:View item in PubMed

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